Added experimental Touch.tilt, Touch.tiltDirection support for Android

ui/events/event.h

Index: ui/events/event.h
diff --git a/ui/events/event.h b/ui/events/event.h
index 56fd74c85d53d17d000fa1b9c6c0796104379056..f919449982062c4f2c38e57cb262e40e6ace3ab4 100644
--- a/ui/events/event.h
+++ b/ui/events/event.h
@@ -491,6 +491,7 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
         radius_x_(model.radius_x_),
         radius_y_(model.radius_y_),
         rotation_angle_(model.rotation_angle_),
+        tilt_(model.tilt_),
         force_(model.force_) {
   }
 
@@ -507,6 +508,7 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
              float radius_x,
              float radius_y,
              float angle,
+             float tilt,
              float force);
 
   ~TouchEvent() override;
@@ -515,6 +517,7 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
   float radius_x() const { return radius_x_; }
   float radius_y() const { return radius_y_; }
   float rotation_angle() const { return rotation_angle_; }
+  float tilt() const { return tilt_; }
   float force() const { return force_; }
 
   // Used for unit tests.
@@ -535,6 +538,10 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
     rotation_angle_ = rotation_angle;
   }
 
+  void set_tilt(float tilt) {
+    tilt_ = tilt;
+  }
+
   void set_force(float force) { force_ = force; }
 
  private:
@@ -551,6 +558,10 @@ class EVENTS_EXPORT TouchEvent : public LocatedEvent {
   // Angle of the major axis away from the X axis. Default 0.0.
   float rotation_angle_;
 
+  // Tilt angle of the stylus away from the perpendicular to the screen.
+  // Default is 0.0.
+  float tilt_;
+
   // Force (pressure) of the touch. Normalized to be [0, 1]. Default to be 0.0.
   float force_;
 };